The subject invention is directed toward the fastener art and, more particularly, to an attachment block structure for providing a fastener receiving surface on a workpiece.
The invention is especially suited for use in the motor vehicle industry to facilitate connection of body panels to vehicle frames and will be described with reference thereto; however, as will become apparent, the invention is capable of broader application and could be used for providing a connection surface on a variety of types of workpieces or frame structures.
During manufacture of vehicle bodies having stamped metal body panels, a variety of techniques are successfully used to join the panels to each other and to the interior frame and support members. Typically, these techniques have included welding, bolting through slotted openings and bolting to precisely located studs welded to the subjacent support members.
With the advent of the use of molded plastic body panels, the prior connecting techniques have not generally been satisfactory. For example, welding cannot normally be used. Moreover, the nature of plastic body panels is such that a very slight misalignment of the mounting openings or studs produces readily visible surface distortion on the panel.
One connecting method which has been used with some success for plastic body panels has been to join relatively large attachment blocks to the subjacent frame or support. After the panels have been precisely positioned, threaded connecting screwd are driven through the panels and into the blocks. Because the blocks have a relatively large screw receiving surface area they do not have to be located with extreme precision.
Attaching blocks of this general type are shown and discussed in U.S. Pat. No. 4,438,971 to Zaydel, et al. The blocks shown therein comprise an open topped, cup-shaped metal housing which is filled with a plastic. The metal housing is joined to the subajacent frame with the plastic filling facing outwardly for receiving the panel connecting screws. The plastic filling can, of course, be readily drilled or machined to allow adjustment of the position of the attached body panel.
The described attaching blocks are definitely an improvement over prior panel attaching methods. One disadvantage is, however, that they require an additional connecting step, i.e., the blocks themselves must be bolted, welded or adhesively bonded to the frame.